Marissa Caseras is a Cuban doctor who is one of the leading experimenters on Boris' condition. She advocates a risky procedure on Boris that involves a bone marrow extraction, of which Hank disapproves. She and Boris are somewhat amorous, and it is her love for Boris that drives her. When attempting to flee Cuba for the United States, she is arrested. Boris later brings her to the Hamptons, where Hank finds out she is pregnant, something for some reason does not wish to tell Boris.